Minimal Lua C++ Example

Example Code

Here is a minimal Lua(V5.1) - C++ example to get one started.

// luaexample.cpp
extern "C" {
  #include "lua.h"
  #include "lualib.h"
  #include "lauxlib.h"
}
#include <string.h>

int main(int argc, char* argv[])
{
      // initialization
      lua_State * L = lua_open();
      luaL_openlibs(L);

      // execute script
      const char lua_script[] = "print('Hello World!')";
      int load_stat = luaL_loadbuffer(L,lua_script,strlen(lua_script),lua_script);
      lua_pcall(L, 0, 0, 0);

      // cleanup
      lua_close(L);
      return 0;
}

Code Explained

Here the lua_open and luaL_openlibs are initialization step in order to prepare the lua_State * L. We store the script that we need to execute in the variable lua_script. The luaL_loadbuffer is used to load the script. The loaded script can be executed by calling lua_pcall(L, 0, 0, 0). The arguments passed to lua_pcall are the lua_State pointer, number of arguments to the script (which is none here), number of values returned (which is none here). The last argument to lua_pcall is the error handler which we will not discuss here.

This needs to be compiled using a C++ compiler and linked to Lua library. When you run the executable, you should see Hello World! printed on the screen.

Conclusion

We looked at a rather simple introductory example of lua interpreter embeded into C++ code.